142 READINGS IN BIOLOGICAL SCIENCE 



to be only good hormones gone wrong. The mooning, lovelorn Romeo 

 of the Mid-Victorian age has become the saxophone addict of today who 

 brays his way into the favor of his ladylove. The languishing Lydias of 

 yesteryear with their scented elegance and euphemistic indirection have 

 given place to the leaping Lenas of today with their cigaretted breath and 

 cocktailed assurance. To what else can such a revolution be due if not to 

 some reversal of the endocrine glands? In these times, indeed, when chil- 

 dren run their parents, freshmen instruct their professors, and wives sup- 

 port their husbands, reversal seems the order of the day, and on what else 

 can we blame it in this scientific age if not on the latest biological dis- 

 covery? 



The facts regarding hormonal effects are so striking in themselves as 

 not to require such epic heightening. In no field of biologic research are 

 more brilliant discoveries being made than in that of the so-called "internal 

 secretions," nor do any recent scientific disclosures hold out greater 

 promise of increasing human welfare and happiness than do these. Since 

 the secretions in question do not pass out from their place of origin 

 through ducts as do ordinary glandular products, but are absorbed directly 

 into the blood or lymph and circulated throughout the body, the glands 

 which produce them are called the ductless or eiidocrme glands. 



Hormones are second in importance only to the nervous system in 

 keeping the parts of the body in harmonious operation. They can stimu- 

 late or inhibit the activity of some organ or tissue in a part of the body 

 far distant from the source of the secretion itself, and what we are, 

 physically, intellectually, and emotionally depends in no small measure 

 upon them. Many physical and even mental abnormalities are being 

 traced to hereditary or acquired imbalance of the endocrine glands. 



In man and other vertebrates the known endocrine organs are special 

 areas in the pancreas called the "islets of Langerhans," the thyroid gland, 

 the parathyroids, the pituitary body, the adrenals, the sex glands, and 

 certain secretory structures in the walls of the upper intestine. Other 

 organs such as the thymus, pineal body, liver and stomach have been 

 suspected of endocrine functions although the evidence is as yet incon- 

 clusive. Hormones have within the past few years also been demonstrated 

 in several kinds of invertebrates, and hormone-Hke substances have even 

 been identified in plant tissues. 



The pancreas is a gland concerned primarily with the elaboration of a 

 digestive fluid which is discharged through the pancreatic duct into the 

 upper intestine. Scattered throughout its substance, however, among the 

 lobules which secrete the ordinary pancreatic juice, are small independent 

 areas of a very different looking tissue known as the islets of Langerhans. 

 These cells secrete a substance known as insuli?! which passes directly 

 into the blood stream and serves, probably in co-operation with the secre- 

 tion of the adrenal glands, to control the metabolism of sugar in the body. 



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